Conventionally, a liquid crystal display device, which incorporates a liquid crystal display panel (display panel) of non-light emitting type, incorporates a backlight unit as well that supplies light to the liquid crystal display panel. It is desirable that the backlight unit generates surface light which spreads throughout the entire region of the surface-shaped liquid crystal display panel. To achieve this, the backlight unit sometimes includes a light guide plate that mixes light from an incorporated light source (e.g., a light emitting device such as an LED and the like) with a high degree.
For example, as shown in FIG. 8, in a backlight unit 149 disclosed in a patent document 1, a light emitting surface 132L of an LED 132 of an LED module mj opposes a light reception surface 111Sa of a light guide plate 111 and supplies light to this light reception surface 111Sa. And, the light guide plate 111 makes the light undergo multiple reflection inside itself and outputs surface light from a top surface 111U.